Conventional detonators, primers, leads, relays and the like consist of cylindrical metal cups into which explosives and other chemicals constituting an explosive train are placed. The explosive train employed in detonators typically contains an ignition explosive charge, a primary explosive charge and a base charge of secondary explosive. The ignition charge, employed as the first component in an explosive train, is extremely sensitive to heat and mechanical shock and is generally considered to include such ignition (initiator) explosives as lead azide, lead styphnate, tetracene, diazodinitrophenol and hexanitromannite. Primary charges are readily ignited by the output energy of the ignition charge, heat, flame and moderate amounts of mechanical shock. Primary charges are generally lead azide, fulminate of mercury, diazodinitrophenol, potassium dinitrobenzofuroxan (KDNBF), etc. The base charge of a detonator is usually a secondary high explosive, which is not readily initiated by heat or mechanical shock but rather by an explosive shock from a primary explosive. Materials such as PETN (pentaerythritol tetranitrate), tetryl (2,4,6-trinitrophenyl methylnitramine), RDX (cyclotrimethylenetrinitramine), HMX (cyclotetramethylenetetranitramine), TNT (2,4,6-trinitrotoluene) and mixtures of TNT with other materials such as RDX, ammonium nitrate, etc., are generally considered to be secondary high explosives.
Detonators, primers, leads and the like are loaded by pressing the loose powdered explosive charges into the cup, usually in increments. According to an alternate technique used for many years, the powdered explosives are compressed into cylindrical pellets and loaded into the metal cups usually with the consolidated loose powdered increments and reconsolidated by pressing to produce the completely loaded detonator.
The aforesaid techniques traditionally employed for producing and loading explosive trains into detonators and the like have many disadvantages. Thus, they involve the hazards usually associated with the handling and processing of powdered explosives. In addition, the incremental loadings and several pressings of the powdered explosives are time consuming and require costly equipment. Further, the production and loading of preformed pellets by pelleting and reconsolidation techniques with loose increments is time consuming and requires the use of auxiliary equipment and operations. These methods also present problems in maintaining uniform product quality and are on the whole relatively inefficient.